This invention relates to the field of integrated circuit manufacturing. More particularly the invention relates to the treatment of platens for rendering them more useful in dry etching processes.
It is desirable to reduce extraneous particulate matter in the environments in which integrated circuits are processed. One reason for this is that when airborne particles are deposited on the surface of the substrate on which the integrated circuits are formed, the particles tend to create processing defects in the integrated circuits, thus reducing the yield of the process and increasing the manufacturing costs of the integrated circuits.
One method by which particles are generated during processing is by the degradation of a surface in a reaction chamber. For example, ceramic materials tend to be highly favored in certain types of reaction chambers because, among other things, they tolerate heat and tend to be non reactive in many environments. However, many ceramic materials tend to have relatively rough surfaces and relatively large pores which crack and spall relatively easily, thus creating particles. In some processes, where gases are distributed though the system, the particles thus created may become entrained in the flowing gases and redeposited on the substrates being process.
For example, dry etching is one method used to form integrated circuits on a substrate, such as a semiconductor substrate. In dry etching processes, such as reactive ion etching, an etching gas is introduced by a gas distribution plate into an etching chamber containing the substrate. One problem encountered in such processes is chipping or degradation of the gas distribution plate, which generate particulates of the plate material. These particles from chipping or other degradation of the plate are carried by the etching gas to the substrate and tend to be detrimental to the integrity and quality of the semiconductor substrate, as described above.
What is needed, therefore, is a system by which gas distribution plates are less susceptible to chipping and generation of particles so as to provide gas distribution plates which are more suitable for their intended purpose.
The above and other needs are met by an improved platen for use in a dry etching process for substrate production. In a preferred embodiment, surfaces of the platen that are susceptible to chipping and particle generation from the dry etching process are coated with silicon carbide to render such surfaces less susceptible to chipping and particle generation. The coating is preferably applied to a thickness of at least about sixty microns by chemical vapor deposition.
It has been observed that the coating is particularly suitable for coating ceramic silicon dioxide distribution plates. Such plates are desirable from a cost basis, but are fragile and prone to chipping and particle generation. By coating the plates in accordance with the invention, the plate is rendered less prone to chipping and particle generation without unduly affecting the desirable cost attributes of the plates. Thus, the invention advantageously enables improved performance in an economical manner.